1. Domain Name System (DNS) Topic 2, Chapter 4 Network Programming Kansas State University at Salina

2. DNS Host name to IP address look up and reverse Hierarchical, distributed, cached database Many services provided by OS  sock.connect( (hostname, port) )  socket.getaddrinfo( hostname, None )

3. Advanced DNS – DNSPython Lookup of MX records for sending e-mail is one example where you might need to program a DNS lookup. Need to add additional package for stand alone DNS lookups.  Book discusses PyDNS, available from source forge.  The package index on python.org suggests that DNSPython is a more popular DNS package.

4. DNSPython http://www.dnspython.org/ Also available from K-State Online Get the MX targets and preferences for a domain: import dns.resolver answers = dns.resolver.query(‘gmail.com', 'MX') for rdata in answers: print 'Host', rdata.exchange, 'has preference', rdata.preference